Yield, time of maximum CO2 exchange rate, and leaf-area index of 'Clemson Spineless' okra are affected by within-row spacing

A 2-year field study was conducted to determine the effects of within-row s pacing (WRS) on CO2 exchange rate (CER),leaf-area index (LAI), and yield of okra [Abelmoschus esculentus (L.) Moench]. Okra cultivar Clemson Spineless was seeded at WRS of 8, 16, 24, 32, 40, and 48 cm in a randomized complete -block design replicated three times. CER and LAI were measured five times at about biweekly intervals between first flowering and final harvest. Frui ts were harvested three times weekly for 7 weeks, There was no pear-to-year variation in CER or LAT. Plants at 8 cm WRS attained maximum CER by 56 day s after planting (DAP), while all other spacings took longer, CER at all WR S declined after 85 DAP. In 8 and 16 cm WRS, maximum LAI developed by 56 DA P, but 69 DAP were required at ail other spacing. Depending on the spacing, LAI regressed linearly or cubically on DAP. Fruit number/plant (FNP), frui t fresh and dry weight/plant (FFW and FDW), and fresh and dry fruit yield/h a (FFY and DFY) were greater in 1991 than in 1990 as a result of more favor able weather during 1991, There was a linear increase in FNP, FFW, and FDW as WRS increased, Conversely; FFY and DFY were highest at 8 cm and decrease d linearly in 1990 and quadratically in 1991 as WRS increased. Results of t his study suggest that okra plants reach maximum CER and LAI earlier and pr oduce higher fruit yield per unit area when spaced close together in the ro w.